Describe the bug

mapset() doesn't translate special key codes.

To Reproduce

Write this in /tmp/t.vim:

nno K :echom 'original mapping'<cr>
let save_map = maparg('K', 'n', 0, 1)
nunmap K
call mapset('n', 0, save_map)
call feedkeys('K')

Start Vim with this shell command:

vim -Nu NONE -S /tmp/t.vim

The command-line is populated with:

echom 'original mapping'<cr>

Notice that <cr> has not been translated into a literal carriage return.

Expected behavior

When K is pressed, the Ex command :echom 'original mapping' is executed, just like it would have been before the mapping was removed by :nunmap.

Environment

• Vim version: 8.2 Included patches: 1-807
• OS: Ubuntu 16.04.6 LTS
• Terminal: XTerm(322)

Additional context

It's as if 'cpo' included the < flag which disables the recognition of special key codes.
However, that's not the issue here; 'cpo' does not contain this flag when started with -Nu NONE (-N resets 'compatible' which resets 'cpo' to aABceFs).